Interface Morphology Description and Quantification of Al–Cu Magnetic Pulse Welding Joints Using X-Ray Micro-computed Tomography

Magnetic pulse welding (MPW) is a relatively new welding technique that has been gaining increasing attention from various industries. MPW allows for the welding of dissimilar materials, such as aluminum and copper, but with specific features at the interface. This study proposes the use of an original approach based on X-ray micro-computed tomography (XCT) to probe and analyze the surface interface between two dissimilar welded components. This method does not require the use of a peeling test to reveal the interface welding. XCT enables a global analysis of the interface and highlights specific features of MPW, such as vortexes and waves, from a new perspective involving metrics. Two vortex morphologies were observed at the interface and were described as standard or broken vortexes. They were classified based on their morphologies, sizes, and densities. Waves and vortexes were found to be inhomogeneous along the length and width of the welding direction at the interface, with sizes that could triple depending on the localization. The surfaces at the interface were numerically extracted and evaluated using roughness parameters. These values represent an increase in the average contact surface area of more than 26% between the two welded components. Vortex features obtained from the XCT analysis were similar to those observed on cross-sectional optical or electronic images, but containing lateral information (creation and collapsing) that are not available with standard cross-sectional images. These results demonstrate the material interlocking at the interface between the materials.